Collet actuator



May 31, 1960 A. DAMIJONAITIS COLLET ACTUATOR Filed NOV. 14, 1955 WAZ N v E N To R Alexana/fu Damgowas BY W ATTORN EYS United States Patent 2,938,500* COLLET AcrUAroR Alexandra Damijonaitis, New Britain, Conn., assignor to Union Manufacturing Company, New Britain, Conn., a corporation of Connecticut Filed Nov. 14, 1955, Ser. No. 546,522

,8 Claims. (Cl. 121-38) My invention relates to a collet or chuck actuator of the iluid pressure type.

It is an object of the invention to provide an improved iluidr pressure actuated chuck or collet actuator.

Another object is to provide an improved uid pressure actuated collet actuator involving a piston and cy1in der means in which the-piston is operated in one direction by pressure uid and in the opposite direction by spring means. f

It is another object to provide an improved piston and cylinder means for collet or chuck actuation which may be applied to and removed, as a unit, from -a spindle."

Anotherl object is to provide improved means for conducting pressure iuidV to a relatively rotatable cylinder and Vpiston without undue leakage orA excessive friction.

Another object is to provide an improved-seal means for conducting pressure fluid to a cylinder and piston means. I l e e It is still another object to'provide means for conducting pressure uid from a stationary ring to a relatively rotatable'piston and cylinder means, and tol provide improved seal means to Vprevent excessive leakage of preslview, through the rear end of a spindle and a collet or chuck actuator, illustrating 'my improved collet or chuck actuator mounted in operative position for a push type collet or chuck; and

Fig. 2 is a fragmentary lview similar to Fig. 1, but illus- `trating the 'invention as applied to a draw type rather than-a push typecollet. e

conducting means has been illustrated.

As illustrated in Fig. l of the drawingspthe rear end theright, as shown'in Fig. 1. Since the collet or` chuck carried; bythe spindle 5 and actuated by the 'collet tube yor chuck actuator 6 may be of conventional or desired .form, theyare not illustrated in' the-drawings.` `In the form illustrated,- a cylinder 7-Y is carried by the; rear end of Vthe `spindle-5 and may be keyed thereto as indicated at 8 and secured in position by screws 9 or the like passing through a nut 10 adjustedly threaded on the spindle. The cylinder is counterbored to receive the extreme rear end of the spindle, as indicated at 11, so that, when the cylinder is in place and secured, the cylinder and spindle are perfectly rigid.

Within the cylinder 7 is a piston 12 having ya rearward extension 13, which preferably ts the rear end of the push tube section 14. This push tube section 14 is preferably part of or a continuation of the standard collet ice tube 6. The tube 14may have a shoulder l15 to fit in the counterbored end of the piston 12, as shown, and a nut 16 on the end of the tube 14 secures the piston eXtension 13 directly to the tube 14. The piston is guided in its reciprocation in the cylinder 7 as by means of projecting buttons 17`betWeen the cylinder and piston, one of those members carrying the buttons and the other having recesses for receiving the buttons. The piston 12 is always urged, and, when free is moved to rearward or lefthand position -by means of a series of springs 18, which may be housed in recesses in the cylinder extension, and may engage plugs 19 engaging the piston directly. When the piston'is so moved to the left, it of course takes with it the tube 14, and the tube 6, if not secured to the tube 14, is also moved to the left by the usual spring of the collet sov as to move the latter to op'en position.

v The piston 12 is movedtoward the right for moving the tubes 14 and '6 to the right for closing the collet, by means of pressure iluid, and one form of pressure fluid In the form shown, the uid is conducted through a standard passage 20 in a ring 21, which is loosely mounted between one cylinder head 22 and -a retainer ring v23 secured to the cylinder extension24 by means such as screws 25. The ring 21 is normally held against rotation while the cylinder and piston rotate with the spindle. The pressure uid passes through the passage 20 and passage 26 in the Ycylinder extension 24 and into the cylinder at the lefthand side of the piston 12, so as to move the latter to the right as viewed in Fig. 1. In order to conduct the pressure fluid Without undue leakage and without undue friction, I providey improved Ymeans in the form of a pair of seal rings 27-28 mounted Within the uid pressure ring 21. and

sealed 's by means of vO-rings or the like 29. YThese seal rings 27,428 sealed in the ring 21 are -held against rotation therein by a screw plug'29 in the ring and tting in radial grooves in the seal rings 27- 28 as clearly shown in Fig. l.l These-seal rings: 27-28 are urged apart as by -meansof compression springs 30 litting in opposed bores:A in "they seallrings 27H28, and there -are contact .lips on the scali-ings 27-'-28 which contact withhard surfaces on the cylinder head 22 yand the ring 23 andthese hard surfaces may be vori hardened steel rings 31 mounted on the head 22 and ring 23. "It will befseen that the areas ofthe seal rings.27'28 -at the outside, as indicated at 32,'- arelabout the sameas theopposed inside areas of 'the `sealing ringsV 27"-28, so that pressure fluid passing Ybetween the rings 27-28 and the clearance spaces 33 acts uponsurfaces`32 so that the pressure will be substantial- 'ly bala'nce'din a longitudinal direction on the seallrings 27g- 28. Thus substantially the only pressure between the seal? rings 27e- 28H and the hardened surfaces on the yhead 22 .andring 23 will be vthe predetermined pressure -created by 'the compression springs 36. The extentof the sealing pressure Iof the seal rings 27-28 maybe ac- 'curately'determined fand ljust the rightpressure obtained -to reduce leakage'eto aminimum, while preventing undue 60 jfriction. between the seal iings v27-28 and the surfaces against'whichthey bear, a'll'regardless of the `pressure of the pressure fluid, Whetherfactingat high pressure-orat exhaust pressure.

The seal rings 27-28 or the abutting rings 3=1 may be formed of a compressed, baked graphite and carbon material, which is very hard, light and wear-resistant. When the seal rings 27-28 are formed of this compressed graphite and carbon material, the coacting surfaces on the members 31 preferably will be formed of steel, since this graphite material and steel when rubbing on each other have a low coeicient of friction and wear will thus be reduced to a minimum and leakage reduced.

It will .be noticed that` the only wear surfaces between the rotating and the stationary parts will be the small contact surfaces between seal rings 27-28 and the rings 31; Theevalve means for controlling thepressure fluid through the passage 2li-will normally be aseparate threeway valve, and since it may be conventional it'has not been illustrated. Y

In the form shown inV Fig. 2, Vthe parts are all substantially the same as heretofore vnoted and-for the 4most part have been given corresponding referencecharacters and have not again been described.

In the form shown in Fig. 2, the longitudinal position of the cylinder and piston and the valve mechanism have been reversed, and some slight changeshave been necessary to accommodate that change.V In the-form shown in Fig. 2, the piston 12' is urged toward the'right, as by means of compression springs 18 instead of toward the left as in Fig. l. The uid pressure ring'Zl is arranged between the cylinder head 22 and a ringpart`23 corresponding to the cylinder head 22 and ring l23 of Fig, l. The piston extension 13 is held'between a shoulder or abutment and the nut 16-on the 'drawtube 6'-, corresponding, respectively, to the shoulder 15 and nut 16 of Fig. l. Thus the piston 12' is moved toward the right by spring pressure and toward the left by uid pressure, and the collet draw tube 6 moves in both directions with the piston. Thus, in the form shown in Fig; 2, the collet or chuck actuator is arranged to actfon apull type collet rather than on the push type collet of Fig. l.

It Will be seen then that I have provided animproved Vchuck or collet actuator mechanism which may be handled as a unit and applied to a spindle and collet tube or other chuck actuating part, and that the parts are easily adaptedvfor operation for either a push, or pull type of collet or chuck. The pressure fluid maybe conducted through a relatively fixed set of parts to the rotating piston and cylinder with a minimum of friction andwear. The parts are all simple and adjustment of the sealed surfaces is automatic by means of spring means, so that the sealing pressure will always remain substantially constant. Y

While the invention has been described in' considerable detail and preferred forms illustrated, it is to be understood that changes and'additions may be madeV within the scope of the invention as defined in the appended claims. Iclam: l. A rotatable cylinder, a pistonY in said cylinder. and rotatable therewith, a xed pressure fluid ring, said ring and cylinder having communicating passage means to convey pressure uid from'said ring to one side of said piston, sealing means between said ring and cylinder, said sealing means including a pair of seal rings `carried by said pressure iluid ring, said cylinder beingrotatable relatively to said rings and having opposed sealing surfaces in circumferentially continuous sealing engagement with each of said rings, means for urgingsaid sealrings into sealing engagement with said sealing surfaces aforesaid,

said seal rings having-passagemeans to transmit pressure uid from said pressure fluid ring togsaid cylinder.

2.' In the combination defined in claim 1, said means for urging said seal rings into sealing; engagement with said sealing surfaces aforesaid, comprising spring means to urge said seal rings into sealing engagement with said sealing surfaces on said cylinder.

3. A cylinder and piston, means for conducting pressure fluid to said rpiston including a pressure fluid ring, a cylinder part coaxial with said pressure fluid ring, said ring and cylinder being relatively rotatable, a pair of seal rings interposed between said duid pressure ring and said cylinder, said cylinder beingrotatable relatively to said seal rings and including axially spaced seal surfaces having circumferentially continuous seal Y,contact with said seal rings, means for urging said seal rings axially into sealing engagement with saidseal surfaces on said.cylin der, said fluid'pressure ring and seal rings and cylinder having registering passage means for conducting pressure fluid to one 'side 'of said piston, for moving the same in one direction.,

4. In the combination defined in claim 3, and spring means for urging said piston in the opposite direction.

5. In the combination defined in claim 3 and circumferentially extending seals betweensaid sealrings and said pressure fluid ring.

6. In the combination defined in claim 3, and pin means engaging said seal rings and vsaidiuidtpressure ring to prevent relative rotation therebetween.

7. A cylinder, said cylinder having a part telescopically received ona spindle end, a nut on said spindle, said cylinder part being securedj to said-nut,y arl-actuator in said spindle and projecting rearwardly therefrom, a piston in said cylinder and having an. extension bored to receive said actuator, anut kon said actuator and abutting the rear end of said piston extension, said cylinder havingr-a cylindrical part surrounding said piston extension, a pressure fluid ringyabout said cylindrical part of said cylinder, seal means between said cylindrical part land said fluid-pressure ring, uid passage, means through said uid pressure ring and said seal means and said cylinder to one side of said piston to admit pressure fluid to move rthe same in one direction, spring means between said piston and cylinder for urging said .piston inthe opposite direction, and guide means between said pistonand cylindertoprevent rotation of said piston in said cylinder.

8. A cylinder and piston, means for conducting pres'- sure fluid to said piston including a pressure fluid ring, a

cylinder part coaxial with said pressure fluid ring, said ring and cylinder being relatively rotatable, a pair of seal ringsv interposed between said fluid pressure ring and said cylinder, said cylinder being rotatable relatively to said sealrings and includingseal surfaces adapted for sealing engagement with said seal rings, means for urging ,-,said seal rings axially into sealing engagement with said seal surfaces on said cylinder, said uid pressure ring and seal rings and cylinder having registering passage means for conducting pressure fluid to one side lof said piston for moving thesamein one direction, said seal rings `having opposed surfaces exposed to pressure uid to balance the same axially.

References Cited in the le of this patent UNITED sTAfrEs'- PATENTS e 

